| isfd | isam file descriptor |
| s1 | pointer to char isstat1 |
| s2 | pointer to char isstat2 |
| s3 | pointer to char isstat3 |
| s4 | pointer to char isstat4 |
the standard DISAM error code.
the value of the global errno is interrogated, if isfd is NULL.
overloaded COBOL status results are translated into s1 through s4, if these are not NULL.
if the COBOL status is not overloaded, the result will be 9090 when an error code is found, or 0000 if the value is zero.
this call is generally intended for use with the COBOL_STATS option, however it should return sensible results in all cases, and so may be used to ensure consistent results in code used across multiple configurations.