GNU/Linux man pages
Livre :
Expressions régulières,
Syntaxe et mise en oeuvre :
GNU/Linux |
RedHat 5.2(Apollo) |
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flock(2) |
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flock − apply or remove an advisory lock on an open file
#include <sys/file.h>
int flock(int fd, int operation)
Apply or remove an advisory lock on an open file. The file is specified by fd. Valid operations are given below:
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LOCK_SH |
Shared lock. More than one process may hold a shared lock for a given file at a given time. | ||
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LOCK_EX |
Exclusive lock. Only one process may hold an exclusive lock for a given file at a given time. | ||
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LOCK_UN |
Unlock. | ||
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LOCK_NB |
Don’t block when locking. May be specified (by or’ing) along with one of the other operations. |
A single file may not simultaneously have both shared and exclusive locks.
A file is locked (i.e., the inode), not the file descriptor. So, dup(2) and fork(2) do not create multiple instances of a lock.
On success, zero is returned. On error, −1 is returned, and errno is set appropriately.
EWOULDBLOCK
The file is locked and the LOCK_NB flag was selected.
4.4BSD (the flock(2) call first appeared in 4.2BSD).
open(2), close(2), dup(2), execve(2), fcntl(2), fork(2). There are also locks.txt and mandatory.txt in /usr/src/linux/Documentation.
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flock(2) | |