If you are using local or global shared resources, you can use the SCHBFR macro to search a buffer.

The format of the SCHBFR macro follows.

label

specifies 1 to 8 characters that provide a symbolic address for the SCHBFR macro.

BFRNO=abs expression

specifies the number of the buffer VSAM is to search first. The buffers preceding it in the buffer pool are not searched. The default is 1; that is, the first buffer is searched first. (If the number is coded in register notation, all registers except 1 and 13 may be used.)

The meaning of BFRNO depends on the total number of buffers in the buffer pool and the number of control intervals in the RBA range given by the RPL ARG parameter. This number is the buffer number relative to the beginning of the RBA range if the total number of buffers in the buffer pool is greater than (3/4 x number of CIs in the RBA range)+3. Otherwise, it is the buffer number on the physical buffer chain.

Restriction: When a data set is in a compressed format, records might be compressed and each buffer might contain an unpredictable amount of data.

RPL=address

specifies the address of the request parameter list defining the SCHBFR request. These RPL parameters have meaning for SCHBFR:

ACB=address

AREA=address

If a buffer is found, the area whose address is specified contains its address (OPTCD=LOC) or a copy of its contents (OPTCD=MVE). With compressed data sets, the contents of the buffer will not be in a readable format. SCHBFR is not recommended for compressed data sets.

AREALEN=abs expression

At least 4 with OPTCD=LOC; at least control interval size with OPTCD=MVE.

ARG=address

ARG gives the address of an 8-byte field containing the beginning and ending control interval RBAs of the range to be searched on. For compressed data sets, the RBA of another record or the address of the next record in a buffer cannot be determined using the length of the current record or the length of the record provided to VSAM.

For extended addressing, the addressof a 16-byte field containing the beginning and ending 8-byte RBAs of the range.

ECB=address

OPTCD=({ASY|SYN},{LOC|MVE})

TRANSID=abs expression

All other RPL parameters are ignored. RPLs are assumed not to be chained. Control interval access is assumed.

If the ACB to which the RPL is related has MACRF=GSR, the program issuing SCHBFR must be in supervisor state with protection key 0 to 7.