The gencat utility shall merge the message text source file msgfile into a formatted message catalog catfile. The file catfile shall be created if it does not already exist. If catfile does exist, its messages shall be included in the new catfile. If set and message numbers collide, the new message text defined in msgfile shall replace the old message text currently contained in catfile.
The following operands shall be supported:
The standard input shall not be used unless a msgfile operand is specified as '-' .
The input files shall be text files.
The following environment variables shall affect the execution of gencat:
The standard output shall not be used unless the catfile operand is specified as '-' .
The standard error shall be used only for diagnostic messages.
The content of a message text file shall be in the format defined as follows. Note that the fields of a message text source line are separated by a single <blank>. Any other <blank>s are considered to be part of the subsequent field.
This line specifies the set identifier of the following messages until the next $set or end-of-file appears. The n denotes the set identifier, which is defined as a number in the range [1, {NL_SETMAX}] (see the <limits.h> header defined in the Base Definitions volume of IEEE Std 1003.1-2001). The application shall ensure that set identifiers are presented in ascending order within a single source file, but need not be contiguous. Any string following the set identifier shall be treated as a comment. If no $set directive is specified in a message text source file, all messages shall be located in an implementation-defined default message set NL_SETD (see the <nl_types.h> header defined in the Base Definitions volume of IEEE Std 1003.1-2001).
This line deletes message set n from an existing message catalog. The n denotes the set number [1, {NL_SETMAX}]. Any string following the set number shall be treated as a comment.
The m denotes the message identifier, which is defined as a number in the range [1, {NL_MSGMAX}] (see the <limits.h> header). The message-text shall be stored in the message catalog with the set identifier specified by the last $set directive, and with message identifier m. If the message-text is empty, and a <blank> field separator is present, an empty string shall be stored in the message catalog. If a message source line has a message number, but neither a field separator nor message-text, the existing message with that number (if any) shall be deleted from the catalog. The application shall ensure that message identifiers are in ascending order within a single set, but need not be contiguous. The application shall ensure that the length of message-text is in the range [0, {NL_TEXTMAX}] (see the <limits.h> header).
Empty lines in a message text source file shall be ignored. The effects of lines starting with any character other than those defined above are implementation-defined.
Text strings can contain the special characters and escape sequences defined in the following table:
| Description | Symbol | Sequence | |||
| <newline> | NL(LF) | \n | |||
| Horizontal-tab | HT | \t | |||
| <vertical-tab> | VT | \v | |||
| <backspace> | BS | \b | |||
| <carriage-return> | CR | \r | |||
| <form-feed> | FF | \f | |||
| Backslash | \ | \\ | |||
| Bit pattern | ddd | \ddd |
The escape sequence "\ddd" consists of backslash followed by one, two, or three octal digits, which shall be taken to specify the value of the desired character. If the character following a backslash is not one of those specified, the backslash shall be ignored.
Backslash ( '\' ) followed by a <newline> is also used to continue a string on the following line. Thus, the following two lines describe a single message string:
1 This line continues \ to the next line
which shall be equivalent to:
1 This line continues to the next line
The following exit values shall be returned:
Default.
The following sections are informative.
Message catalogs produced by gencat are binary encoded, meaning that their portability cannot be guaranteed between different types of machine. Thus, just as C programs need to be recompiled for each type of machine, so message catalogs must be recreated via gencat.
iconv() , the Base Definitions volume of IEEE Std 1003.1-2001, <limits.h>, <nl_types.h>