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readlink - read the contents of a symbolic link
#include <unistd.h>
ssize_t readlink(const char *restrict path, char *restrict
buf,
size_t bufsize);
The readlink() function shall place the contents of the symbolic link referred to by path in the buffer buf which has size bufsize. If the number of bytes in the symbolic link is less than bufsize, the contents of the remainder of buf are unspecified. If the buf argument is not large enough to contain the link content, the first bufsize bytes shall be placed in buf.
If the value of bufsize is greater than {SSIZE_MAX}, the result is implementation-defined.
Upon successful completion, readlink() shall return the count of bytes placed in the buffer. Otherwise, it shall return a value of -1, leave the buffer unchanged, and set errno to indicate the error.
The readlink() function shall fail if:
The readlink() function may fail if:
The following sections are informative.
The following example shows how to read the name of a symbolic link named /modules/pass1.
#include <unistd.h>
char buf[1024];
ssizet_t len;
...
if ((len = readlink("/modules/pass1", buf, sizeof(buf)-1)) != -1)
buf[len] = '\0';
Conforming applications should not assume that the returned contents of the symbolic link are null-terminated.
Since IEEE Std 1003.1-2001 does not require any association of file times with symbolic links, there is no requirement that file times be updated by readlink(). The type associated with bufsiz is a size_t in order to be consistent with both the ISO C standard and the definition of read(). The behavior specified for readlink() when bufsiz is zero represents historical practice. For this case, the standard developers considered a change whereby readlink() would return the number of non-null bytes contained in the symbolic link with the buffer buf remaining unchanged; however, since the stat structure member st_size value can be used to determine the size of buffer necessary to contain the contents of the symbolic link as returned by readlink(), this proposal was rejected, and the historical practice retained.
lstat() , stat() , symlink() , the Base Definitions volume of IEEE Std 1003.1-2001, <unistd.h>
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