__last_op values

The __last_op field is the most important of the __amrc fields. It defines the last I/O operation C/C++ was performing at the time of the I/O error. You should note that the structure is neither cleared nor set by non-I/O operations, so querying this field outside of a SIGIOERR handler should only be done immediately after I/O operations. Table 1 lists __last_op values you could receive and where to look for further information.

Table 1. __last_op values and diagnosis information

Value	Further Information
__IO_INIT	Will never be seen by SIGIOERR exit value given at initialization.
__BSAM_OPEN	Sets __error with return code from OS OPEN macro.
__BSAM_CLOSE	Sets __error with return code from OS CLOSE macro.
__BSAM_READ	No return code (either __abend (errno == 92) or __msg (errno == 66) filled in).
__BSAM_NOTE	NOTE returned 0 unexpectedly, no return code.
__BSAM_POINT	This will not appear as an error lastop.
__BSAM_WRITE	No return code (either __abend (errno == 92) or __msg (errno == 65) filled in).
__BSAM_CLOSE_T	Sets __error with return code from OS CLOSE TYPE=T.
__BSAM_BLDL	Sets __error with return code from OS BLDL macro.
__BSAM_STOW	Sets __error with return code from OS STOW macro.
__TGET_READ	Sets __error with return code from TSO TGET macro.
__TPUT_WRITE	Sets __error with return code from TSO TPUT macro.
__IO_DEVTYPE	Sets __error with return code from I/O DEVTYPE macro.
__IO_RDJFCB	Sets __error with return code from I/O RDJFCB macro.
__IO_TRKCALC	Sets __error with return code from I/O TRKCALC macro.
__IO_OBTAIN	Sets __error with return code from I/O CAMLST OBTAIN.
__IO_LOCATE	Sets __error with return code from I/O CAMLST LOCATE.
__IO_CATALOG	Sets __error with return code from I/O CAMLST CAT. The associated macro is CATALOG.
__IO_UNCATALOG	Sets __error with return code from I/O CAMLST UNCAT. The associated macro is CATALOG.
__IO_RENAME	Sets __error with return code from I/O CAMLST RENAME.
__SVC99_ALLOC	Sets __alloc structure with info and error codes from SVC 99 allocation.
__SVC99_ALLOC_NEW	Sets __alloc structure with info and error codes from SVC 99 allocation of NEW file.
__SVC99_UNALLOC	Sets __unalloc structure with info and error codes from SVC 99 unallocation.
__C_TRUNCATE	Set when C or C++ truncates output data. Usually, this is data written to a text file with no newline such that the record fills up to capacity and subsequent characters cannot be written. For a record I/O file this refers to an fwrite() writing more data than the record can hold. Truncation is always rightmost data. There is no return code.
__C_FCBCHECK	Set when C or C++ FCB is corrupted. This is due to a pointer corruption somewhere. File cannot be used after this.
__C_DBCS_TRUNCATE	This occurs when writing DBCS data to a text file and there is no room left in a physical record for anymore double byte characters. A new-line is not acceptable at this point. Truncation will continue to occur until an SI is written or the file position is moved. Cannot happen if MB_CUR_MAX is 1.
__C_DBCS_SO_TRUNCATE	This occurs when there is not enough room in a record to start any DBCS string or else when a redundant SO is written to the file before an SI. Cannot happen if MB_CUR_MAX is 1.
__C_DBCS_SI_TRUNCATE	This occurs only when there was not enough room to start a DBCS string and data was written anyways, with an SI to end it. Cannot happen if MB_CUR_MAX is 1.
__C_DBCS_UNEVEN	This occurs when an SI is written before the last double byte character is completed, thereby forcing C or C++ to fill in the last byte of the DBCS string with a padding byte X'FE'. Cannot happen if MB_CUR_MAX is 1.
__C_CANNOT_EXTEND	This occurs when an attempt is made to extend a file that allows writing, but cannot be extended. Typically this is a member of a partitioned data set being opened for update.
__VSAM_OPEN_FAIL	Set when a low level VSAM OPEN fails, sets __rc and __fdbk fields in the __amrc struct.
__VSAM_OPEN_ESDS	Does not indicate an error; set when the low level VSAM OPEN succeeds, and the file type is ESDS.
__VSAM_OPEN_RRDS	Does not indicate an error; set when the low level VSAM OPEN succeeds, and the file type is RRDS.
__VSAM_OPEN_KSDS	Does not indicate an error; set when the low level VSAM OPEN succeeds, and the file type is KSDS.
__VSAM_OPEN_ESDS_PATH	Does not indicate an error; set when the low level VSAM OPEN succeeds, and the file type is ESDS PATH.
__VSAM_OPEN_KSDS_PATH	Does not indicate an error; set when the low level VSAM OPEN succeeds, and the file type is KSDS PATH.
__VSAM_MODCB	Set when a low level VSAM MODCB macro fails, sets __rc and __fdbk fields in the __amrc struct.
__VSAM_TESTCB	Set when a low level VSAM TESTCB macro fails, sets __rc and __fdbk fields in the __amrc struct.
__VSAM_SHOWCB	Set when a low level VSAM SHOWCB macro fails, sets __rc and __fdbk fields in the __amrc struct.
__VSAM_GENCB	Set when a low level VSAM GENCB macro fails, sets __rc and __fdbk fields in the __amrc struct.
__VSAM_GET	Set when the last op was a low level VSAM GET; if the GET fails, sets __rc and __fdbk in the __amrc struct.
__VSAM_PUT	Set when the last op was a low level VSAM PUT; if the PUT fails, sets __rc and __fdbk in the __amrc struct.
__VSAM_POINT	Set when the last op was a low level VSAM POINT; if the POINT fails, sets __rc and __fdbk in the __amrc struct.
__VSAM_ERASE	Set when the last op was a low level VSAM ERASE; if the ERASE fails, sets __rc and __fdbk in the __amrc struct.
__VSAM_ENDREQ	Set when the last op was a low level VSAM ENDREQ; if the ENDREQ fails, sets __rc and __fdbk in the __amrc struct.
__VSAM_CLOSE	Set when the last op was a low level VSAM CLOSE; if the CLOSE fails, sets __rc and __fdbk in the __amrc struct.
__QSAM_GET	__error is not set (if abend (errno == 92), __abend is set, otherwise if read error (errno == 66), look at __msg.
__QSAM_PUT	__error is not set (if abend (errno == 92), __abend is set, otherwise if write error (errno == 65), look at __msg.
__QSAM_TRUNC	This is an intermediate operation. You will only see this if an I/O abend occurred.
__QSAM_FREEPOOL	This is an intermediate operation. You will only see this if an I/O abend occurred.
__QSAM_CLOSE	Sets __error to result of OS CLOSE macro.
__QSAM_OPEN	Sets __error to result of OS OPEN macro.
__CMS_OPEN	Sets __error to result of FSOPEN.
__CMS_CLOSE	Sets __error to result of FSCLOSE.
__CMS_READ	Sets __error to result of FSREAD.
__CMS_WRITE	Sets __error to result of FSWRITE.
__CMS_STATE	Sets __error to result of FSSTATE.
__CMS_ERASE	Sets __error to result of FSERASE.
__CMS_RENAME	Sets __error to result of CMS RENAME command.
__CMS_EXTRACT	Sets __error to result of DMS EXTRACT call.
__CMS_LINERD	Sets __error to result of LINERD macro.
__CMS_LINEWRT	Sets __error to result of LINEWRT macro.
__CMS_QUERY	__error is not set.
__HSP_CREATE	Indicates last op was a DSPSERV CREATE to create a hiperspace for a hiperspace memory file. If CREATE fails, stores abend code in __amrc__code__abend__syscode, reason code in __amrc__code__abend__rc.
__HSP_DELETE	Indicates last op was a DSPSERV DELETE to delete a hiperspace for a hiperspace memory file during termination. If DELETE fails, stores abend code in __amrc__code__abend__syscode, reason code in __amrc__code__abend__rc.
__HSP_READ	Indicates last op was a HSPSERV READ from a hiperspace. If READ fails, stores abend code in __amrc__code__abend__syscode, reason code in __amrc__code__abend__rc.
__HSP_WRITE	Indicates last op was a HSPSERV WRITE to a hiperspace. If WRITE fails, stores abend code in __amrc__code__abend__syscode, reason code in __amrc__code__abend__rc.
__HSP_EXTEND	Indicates last op was a HSPSERV EXTEND during a write to a hiperspace. If EXTEND fails, stores abend code in __amrc__code__abend__syscode, reason code in __amrc__code__abend__rc.
__CICS_WRITEQ_TD	Sets __error with error code from EXEC CICS® WRITEQ TD.
__LFS_OPEN	Sets __error with reason code from HFS services. Reason code from HFS services must be broken up. The low order 2 bytes can be looked up in z/OS UNIX System Services Programming: Assembler Callable Services Reference.
__LFS_CLOSE	Sets __error with reason code from HFS services. Reason code from HFS services must be broken up. The low order 2 bytes can be looked up in z/OS UNIX System Services Programming: Assembler Callable Services Reference.
__LFS_READ	Sets __error with reason code from HFS services. Reason code from HFS services must be broken up. The low order 2 bytes can be looked up in z/OS UNIX System Services Programming: Assembler Callable Services Reference.
__LFS_WRITE	Sets __error with reason code from HFS services. Reason code from HFS services must be broken up. The low order 2 bytes can be looked up in z/OS UNIX System Services Programming: Assembler Callable Services Reference.
__LFS_LSEEK	Sets __error with reason code from HFS services. Reason code from HFS services must be broken up. The low order 2 bytes can be looked up in z/OS UNIX System Services Programming: Assembler Callable Services Reference.
__LFS_FSTAT	Sets __error with reason code from HFS services. Reason code from HFS services must be broken up. The low order 2 bytes can be looked up in z/OS UNIX System Services Programming: Assembler Callable Services Reference.