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关于COBOL文件返回码的处理．
(2012-05-19 20:53:57)
标签：
杂谈 |
分类： 大型机 |
由于本人目前也还是处于菜鸟一枚，当然，在编写COBOL程序的时候，避免不了存在各种代码的规范的问题．对文件返回码的处理，就是这规范当中一条不可或缺的规则．一个好的，有经验的COBOL程序员，必定是能对文件的各种返回码处理的有条不紊．
cobol的文件返回码有很多，个人绝的，你要是去死记硬背的话，估计是有的一背了，反正笔者的记忆力是已经不行了，基本上都是看文档．话说回来，这东西其实完全不需要去记，用多了，那些文件的返回码简直就是小菜一碟啊，文档什么的，根本不需要，不就是几个数字么，一共就没那么些状态，还能有很多中组合不成？下面是一些文件的返回码，大家可以参考参考：
00
Successful completion
02
ndexed
files only. Possible causes:
For a READ statement, the key value for the current key is equal to the value of that same key in the next record in the current key of reference.
For a WRITE or REWRITE statement, the record just written created a duplicate key value for at least one alternate record key for which duplicates are allowed.
04
The length of the record being processed does not conform to the fixed file attributes for that file.
05
The referenced optional file is not present at the time the OPEN statement is executed.
06
Attempted to write to a file that has been opened for input.
07
Sequential files only. For an OPEN or CLOSE statement with the REEL/UNIT phrase the referenced file is a non-reel/unit medium.
08
Attempted to read from a file opened for output.
09
No room in directory or directory does not exist.
10
No next logical record exists. You have reached the end of the file.
12
Attempted to open a file that is already open
13
File not found.
14
Relative files only. The number of significant digits in the relative record number is larger than the size of the relative key data item described for that file.
Too many files open simultaneously (Micro Focus).
15
Too many indexed files open (Micro Focus)
16
Too many device files open (Micro Focus).
17
Record error: probably zero length (Micro Focus).
18
Read part record error: EOF before EOR or file open in wrong mode (Micro Focus).
19
Rewrite
error: open mode or access mode wrong (Micro Focus).
20
Device or resource busy (Micro Focus).
21
Sequentially accessed files only. Indicates a sequence error. The
ascending key requirements of successive record key values has been
violated, or, the prime record key value has been changed by a
COBOL program between successful execution of a READ statement and
execution of the next REWRITE statement for that file.
22
Indexed and
relative files only. Indicates a duplicate key condition. Attempt
has been made to store a record that would create a duplicate key
in the indexed or relative file OR a duplicate alternate record key
that does not allow duplicates.
23
Indicates
no record found. An attempt has been made to access a record,
identified by a key, and that record does not exist in the file.
Alternatively a START or READ operation has been tried on an
optional input file that is not present.
24
Relative
and indexed files only. Indicates a boundary violation. Possible
causes:
Attempting to write beyond the externally defined boundaries of a file
Attempting a sequential WRITE operation has been tried on a relative file, but the number of significant digits in the relative record number is larger than the size of the relative key data item described for the file.
30
The I/O
statement was unsuccessfully executed as the result of a boundary
violation for a sequential file or as the result of an I/O error,
such as a data check parity error, or a transmission error.
32
Too many
Indexed files opened. This can also happen when a sequential file
is open for input and an attempt is made to open the same file for
output.(Run Time System (RTS) message by Micro Focus).
34
The I/O
statement failed because of a boundary violation. This condition
indicates that an attempt has been made to write beyond the
externally defined boundaries of a sequential file.
35
An OPEN
operation with the I-O, INPUT, or EXTEND phrases has been tried on
a non-OPTIONAL file that is not present. Trying to open a file that
does not exist.
May need to map the COBOL file name to the physical file name. (Micro Focus, refer to the ASSIGN(EXTERNAL) directive)
37
An OPEN
operation has been tried on a file which does not support the open
mode specified in the OPEN statement.
38
An OPEN
operation has been tried on a file previously closed with a
lock.
39
A conflict has been detected between the actual file attributes and the attributes specified for the file in the program.This is usually caused by a conflict with record-length, key-length, key-position or file organization.
Other possible causes are:
1. Alternate indexes are incorrectly defined (Key length or position, duplicates or sparse parameters).
2. The Recording Mode is Variable or Fixed or not defined the same as when the file was created..
41
An OPEN
operation has been tried on file already opened.
42
A CLOSE
operation has been tried on file already closed.
43
Files in sequential access mode. The last I/O statement executed for the file, before the execution of a DELETE or REWRITE statement, was not a READ statement.
44
A boundary
violation exists. Possible causes:
Attempting to WRITE or REWRITE a record that is larger than the largest, or smaller than the smallest record allowed by the RECORD IS VARYING clause of the associated file
Attempting to REWRITE a record to a file and the record is not the same size as the record being replaced.
46
A
sequential READ operation has been tried on a file open in the
INPUT or I-O mode but no valid next record has been
established.
47
A READ or
START operation has been tried on a file not opened INPUT or
I-O.
48
A WRITE
operation has been tried on a file not opened in the OUTPUT, I-O,
or EXTEND mode, or on a file open I-O in the sequential access
mode.
49
A DELETE or
REWRITE operation has been tried on a file that is not opened
I-O.
其实，文件返回码有很多种哈，可以自己去查阅相关的文档，这里只是列举了其中的一部分．其实，一般需要处理的那就是35,一般情况下，都是找不到文件，返回值为35.
那么怎么捕获文件的返回码呢？方法很简单，你只需要在FILE-CONTROLs声明文件的时候，加上个FILE STATUS IS
XXXXX，然后在数据部吧XXXXX定义就OK，看了上面列举的返回码，你就应该知道，XXXXX一定是计算型的数据类型了，而且至少是两位，在数据布申明的时候，那就千万别把它整成字符型什么的．用个例子说明下吧：
...............................
ENVIRONMENT DIVISION.
INPUT-OUTPUT SECTION.
FILE-CONTROL.
SELECT IN-FILE ASSIGN TO IN-FILE
FILE STATUS IS IN-FILE-STATUS.
................................
................................
DATA DIVISION.
................................
................................
WORKNG-STORAGE SECTION.
77 IN-FILE-STATUS PIC 99.
................................
................................
PROCEDURE DIVISION.
...............................
...............................
003-OPEN-PART.
OPEN INPUT IN-FILE.
IF IN-FILE STATUS NOT = 0
PERFORM 004-END-PART.
cobol的文件返回码有很多，个人绝的，你要是去死记硬背的话，估计是有的一背了，反正笔者的记忆力是已经不行了，基本上都是看文档．话说回来，这东西其实完全不需要去记，用多了，那些文件的返回码简直就是小菜一碟啊，文档什么的，根本不需要，不就是几个数字么，一共就没那么些状态，还能有很多中组合不成？下面是一些文件的返回码，大家可以参考参考：
00
Successful completion
02
For a READ statement, the key value for the current key is equal to the value of that same key in the next record in the current key of reference.
For a WRITE or REWRITE statement, the record just written created a duplicate key value for at least one alternate record key for which duplicates are allowed.
04
The length of the record being processed does not conform to the fixed file attributes for that file.
05
The referenced optional file is not present at the time the OPEN statement is executed.
06
Attempted to write to a file that has been opened for input.
07
Sequential files only. For an OPEN or CLOSE statement with the REEL/UNIT phrase the referenced file is a non-reel/unit medium.
08
Attempted to read from a file opened for output.
09
No room in directory or directory does not exist.
10
No next logical record exists. You have reached the end of the file.
12
Attempted to open a file that is already open
13
File not found.
14
Relative files only. The number of significant digits in the relative record number is larger than the size of the relative key data item described for that file.
Too many files open simultaneously (Micro Focus).
15
Too many indexed files open (Micro Focus)
16
Too many device files open (Micro Focus).
17
Record error: probably zero length (Micro Focus).
18
Read part record error: EOF before EOR or file open in wrong mode (Micro Focus).
19
20
Device or resource busy (Micro Focus).
21
22
23
24
Attempting to write beyond the externally defined boundaries of a file
Attempting a sequential WRITE operation has been tried on a relative file, but the number of significant digits in the relative record number is larger than the size of the relative key data item described for the file.
30
32
34
35
May need to map the COBOL file name to the physical file name. (Micro Focus, refer to the ASSIGN(EXTERNAL) directive)
37
38
39
A conflict has been detected between the actual file attributes and the attributes specified for the file in the program.This is usually caused by a conflict with record-length, key-length, key-position or file organization.
Other possible causes are:
1. Alternate indexes are incorrectly defined (Key length or position, duplicates or sparse parameters).
2. The Recording Mode is Variable or Fixed or not defined the same as when the file was created..
41
42
43
Files in sequential access mode. The last I/O statement executed for the file, before the execution of a DELETE or REWRITE statement, was not a READ statement.
44
Attempting to WRITE or REWRITE a record that is larger than the largest, or smaller than the smallest record allowed by the RECORD IS VARYING clause of the associated file
Attempting to REWRITE a record to a file and the record is not the same size as the record being replaced.
46
47
48
49
其实，文件返回码有很多种哈，可以自己去查阅相关的文档，这里只是列举了其中的一部分．其实，一般需要处理的那就是35,一般情况下，都是找不到文件，返回值为35.
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