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In this example, the strtok() function is used to parse the first argument into colon-delimited tokens; it outputs each word from the string on a new line. Assume that PATH is "/usr/bin:/usr/sbin:/sbin".
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char *token;
char *path = getenv("PATH");
token = strtok(path, ":");
puts(token);
while (token = strtok(0, ":")) {
puts(token);
}
printf("PATH: %s\n", path);
/* PATH is now just "/usr/bin" */
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In this compliant solution, the string being tokenized is copied into a temporary buffer which is not referenced after the call to strtok():
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char *token;
const char *path = getenv("PATH");
/* PATH is something like "/usr/bin:/bin:/usr/sbin:/sbin" */
char *copy = (char *)malloc(strlen(path) + 1);
if (copy == NULL) {
/* handle error */
}
strcpy(copy, path);
token = strtok(copy, ":");
puts(token);
while (token = strtok(0, ":")) {
puts(token);
}
free(copy);
copy = NULL;
printf("PATH: %s\n", path);
/* PATH is still "/usr/bin:/bin:/usr/sbin:/sbin" */
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