1 | /**************************************** |
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2 | * Computer Algebra System SINGULAR * |
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3 | ****************************************/ |
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4 | /* $id:$ */ |
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5 | |
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6 | /* find_exec.c -- Find a program, given an argv[0] |
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7 | Copyright (C) 1996 Free Software Foundation, Inc. |
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8 | Copyright (C) 1990 by W. Wilson Ho. |
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9 | This file is part of the GNU Dld Library. */ |
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10 | |
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11 | /* Adapted for use with Singular by obachman@mathematik.uni-kl.de 4/98*/ |
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12 | |
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13 | #include "mod2.h" |
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14 | |
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15 | #if ! defined(MSDOS) && ! defined(__MWERKS__) |
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16 | |
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17 | #include <unistd.h> /* always defiend */ |
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18 | #include <stdlib.h> |
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19 | #include <strings.h> |
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20 | |
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21 | #include "mmemory.h" |
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22 | |
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23 | #ifndef MAXPATHLEN |
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24 | #define MAXPATHLEN 1024 |
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25 | #endif |
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26 | |
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27 | |
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28 | /* Do not return copies of sth, but simply the strings |
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29 | -- we make copies later */ |
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30 | #define copy_of(string) mstrdup(string) |
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31 | |
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32 | /* ABSOLUTE_FILENAME_P (fname): True if fname is an absolute filename */ |
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33 | #ifdef atarist |
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34 | #define ABSOLUTE_FILENAME_P(fname) ((fname[0] == '/') || \ |
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35 | (fname[0] && (fname[1] == ':'))) |
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36 | #else |
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37 | #define ABSOLUTE_FILENAME_P(fname) (fname[0] == '/') |
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38 | #endif /* atarist */ |
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39 | |
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40 | /* Return the absolute name of the program named NAME. This function |
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41 | searches the directories in the PATH environment variable if PROG |
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42 | has no directory components. */ |
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43 | #ifndef HAVE_READLINK |
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44 | char * find_executable (const char *name) |
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45 | #else |
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46 | char * find_executable_link (const char *name) |
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47 | #endif |
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48 | { |
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49 | char *search; |
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50 | char *p; |
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51 | char *extra = NULL; |
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52 | char tbuf[MAXPATHLEN]; |
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53 | |
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54 | if (ABSOLUTE_FILENAME_P(name)) |
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55 | { |
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56 | /* If we can execute the named file then return it. */ |
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57 | if (! access (name, X_OK)) |
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58 | return copy_of (name); |
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59 | } |
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60 | else |
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61 | { |
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62 | if (((name[0] == '.') && (name[1] == '/')) || |
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63 | ((name[0] == '.') && (name[1] == '.') && (name[2] == '/'))) |
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64 | { |
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65 | strcpy (tbuf, (name[1] == '.' ? ".." : ".")); |
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66 | |
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67 | #ifdef HAVE_GETCWD |
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68 | getcwd (tbuf, MAXPATHLEN); |
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69 | #else |
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70 | # ifdef HAVE_GETWD |
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71 | getwd (tbuf); |
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72 | # endif |
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73 | #endif |
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74 | strcat (tbuf, "/"); |
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75 | strcat (tbuf, name); |
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76 | return copy_of (tbuf); |
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77 | } |
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78 | |
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79 | |
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80 | search = getenv("PATH"); |
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81 | /* for winnt under msdos, cwd is implictly in the path */ |
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82 | #ifdef WINNT |
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83 | p = getenv("SHELL"); |
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84 | if (p == NULL || strlen(p) < 2) |
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85 | { |
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86 | /* we are under msdos display */ |
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87 | extra = (char*) AllocL((search != NULL ? strlen(search) : 0) + 3); |
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88 | strcpy(extra, ".:"); |
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89 | if (search != NULL) strcat(extra, search); |
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90 | search = extra; |
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91 | } |
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92 | #endif |
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93 | p = search; |
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94 | |
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95 | if (p != NULL) |
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96 | { |
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97 | while (1) |
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98 | { |
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99 | char *next; |
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100 | next = tbuf; |
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101 | |
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102 | /* Copy directory name into [tbuf]. */ |
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103 | /* This is somewhat tricky: empty names mean cwd, w.r.t. some |
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104 | shell spec */ |
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105 | while (*p && *p != ':') |
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106 | *next ++ = *p ++; |
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107 | *next = '\0'; |
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108 | |
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109 | if ((tbuf[0] == '.' && tbuf[1] == '\0') || tbuf[0] == '\0') { |
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110 | #ifdef HAVE_GETCWD |
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111 | getcwd (tbuf, MAXPATHLEN); |
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112 | #else |
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113 | # ifdef HAVE_GETWD |
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114 | getwd (tbuf); |
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115 | # endif |
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116 | #endif |
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117 | } |
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118 | |
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119 | if (tbuf[strlen(tbuf)-1] != '/') strcat(tbuf, "/"); |
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120 | strcat (tbuf, name); |
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121 | |
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122 | /* If we can execute the named file, then return it. */ |
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123 | if (! access (tbuf, X_OK)) |
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124 | { |
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125 | #ifdef WINNT |
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126 | if (extra != NULL) |
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127 | FreeL(extra); |
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128 | #endif |
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129 | return copy_of (tbuf); |
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130 | } |
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131 | |
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132 | if (*p != '\0') |
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133 | { |
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134 | p ++; |
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135 | } |
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136 | else |
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137 | { |
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138 | break; |
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139 | } |
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140 | |
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141 | } |
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142 | } |
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143 | } |
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144 | |
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145 | return NULL; |
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146 | } |
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147 | |
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148 | #ifdef HAVE_READLINK |
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149 | char * find_executable (const char *name) |
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150 | { |
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151 | char * link = find_executable_link(name); |
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152 | char buf[MAXPATHLEN]; |
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153 | int ret; |
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154 | |
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155 | if (link == NULL && (ret=readlink(name, buf, MAXPATHLEN)) > 0) |
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156 | { |
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157 | buf[ret] ='\0'; |
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158 | link = find_executable_link(buf); |
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159 | } |
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160 | if (link != NULL && (ret=readlink(link, buf, MAXPATHLEN)) > 0) |
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161 | { |
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162 | char *p = strrchr(link, '/'); |
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163 | char *executable; |
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164 | |
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165 | |
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166 | if(p!=NULL) *(p+1)='\0'; |
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167 | buf[ret]='\0'; |
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168 | |
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169 | if (buf[0] != '/') |
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170 | { |
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171 | executable = (char*) AllocL(strlen(link) + ret + 1); |
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172 | strcpy(executable, link); |
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173 | strcat(executable, buf); |
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174 | } |
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175 | else |
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176 | { |
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177 | executable = copy_of(buf); |
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178 | } |
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179 | |
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180 | FreeL(link); |
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181 | return executable; |
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182 | } |
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183 | |
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184 | return link; |
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185 | } |
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186 | #endif /* HAVE_READLINK */ |
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187 | |
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188 | #else |
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189 | |
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190 | char* find_executable (const char *name) |
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191 | { |
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192 | return NULL; |
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193 | } |
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194 | |
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195 | #endif /* #if ! defined(MSDOS) && ! defined(__MWERKS__) && defined(HAVE_SYS_TYPES_H) && defined(HAVE_PWD_H)&&defined(HAVE_SYS_PARAM_H) */ |
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196 | |
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197 | |
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