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Dynamically locks a file. A call to FLOCK is required before any attempt is made to read or modify a file with shared access. | | | |  | NOTE: The file system does not guarantee exclusive access, even when FLOCK and FUNLOCK are used, unless all programs that access the file cooperate by using locking. A program that opens the file with dynamic locking enabled will still be allowed to modify the file, even if it never calls FLOCK. | | | | |
Syntax | |
I16V U16V
FLOCK(filenum,lockflag);
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Parameters | |
- filenum
16-bit signed integer by value (required) Passes the file number of the file whose global resource identification number (RIN) is to be locked. - lockflag
16-bit unsigned integer by value (required) Specify either conditional or unconditional locking by setting bit (15:1) as follows: - Value
Meaning - 0
Locking takes place only if the file's global RIN is not currently locked. If the RIN is locked, control returns immediately to the calling process, with condition code CCG. - 1
Locking takes place unconditionally. If the file cannot be locked immediately, the calling process suspends until the file can be locked.
Condition Codes | |
The following condition codes are possible when lockflag bit (15:1)=1: - CCE
Request granted. - CCG
Not returned. - CCL
Request denied. This file was not opened with the dynamic locking aoption bit (10:1) specified in the FOPEN/HPFOPEN intrinsic.
The following condition codes are possible when lockflag bit (15:1)=0: - CCE
Request granted. - CCG
Request denied because the file was locked by another process. - CCL
Request denied. This file was not opened with the dynamic locking aoption bit (10:1) specified in the FOPEN/HPFOPEN intrinsic.
Refer to this intrinsic in the MPE/iX Intrinsics Reference Manual (32650-90028) for other codes pertaining to KSAM files. |
