FREAD
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| E0300 Edition 4 ♥ | |
| E0394 Edition 3 |
| Syntax | Functional Return | Parameters | Operation Notes | Condition Codes |
Syntax
I16 I16V UDS I16V lgth := FREAD (filenum, buffer, length);
Functional Return
- lgth
16-bit signed integer (assigned functional return)
Returns the length of the data transferred to buffer:
If a negative value is passed in the length parameter,the lgth is a positive value indicating the number of bytes transferred.
If a positive value is passed in the length parameter, the lgth is a positive value indicating the number of halfwords transferred.
If a value of 0 is passed in the length parameter, the position is identified, but the data is not returned.
Parameters
- filenum
16-bit signed integer by value (required)
Passes the file number of the file to be read.
- buffer
user-defined structure (required)
Returns the record that was read. This structure must be large enough to hold all of the information to be transferred.
- length
16-bit signed integer by value (required)
Passes the length of the data to be transferred to buffer. If this value is positive, it signifies the length in halfwords. If negative, it signifies the length in bytes. If zero, no transfer occurs.
If length is larger than the size of the logical record, transfer is limited to the length of the logical record. If less than the size of the logical record, the transfer is limited to the length specified.
Operation Notes
This intrinsic reads the advance flag and advances to the next record if the flag is set to TRUE. It positions the logical record pointer and the physical pointer to the appropriate record. When its function is complete, it sets the advance flag to TRUE. When the logical end-of-data is encountered, CCG is returned to the process.
Condition Codes
- CCE
Request granted. The information was read.
- CCG
Request denied. The logical end-of-data was encountered during reading.
- CCL
Request denied. The information was not read because an error occurred.
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FPOINT |
FREADBYKEY |