OS_ReadArgs (changes)

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OS SWI Calls

» OS_ReadArgs

OS_ReadArgs

(SWI &49)

Use

The purpose of this call is to scan the input string, and places values in output buffer according to the syntax string.

It is generally used to extract parameters from the command line following a call to OS_GetEnv and using the value of R0 as the input string. As such this call should be used at the start of a program before the first Wimp_Poll.

This call will return error 490 “Parameters not recognised” if:

• the input string has a keyword that is not specified in the syntax string
• the syntax string has a keyword with qualifier “/A” that is not in the input string
• the input string has items which have not been matched to the syntax string

This call will return error 491 “Argument repeated” if a parameter is repeated in the input string.

This call will also call OS_EvaluateExpression and OS_GSTrans if the qualifiers “/E” and “/G”, respectively, are specified in the syntax string, and any errors from them will also be returned.

In the event of an error, this call does not give any indication as to which item in the input string has caused the problem.

See also

• OS_ReadArgs Input String
• OS_ReadArgs Output Buffer
• OS_ReadArgs Syntax String
• OS_ReadArgs Examples Page