Re: How to detect NULL in VarChar (C function)

Benno Pütz <puetz@mpipsykl.mpg.de> writes:
> I have not been able to find a description of how to detect NULL values 
> in VarChar variables passed to C-functions to catch those cases.

Use PG_ARGISNULL().  See
33.7.4. Calling Conventions Version 1 for C-Language Functions
at
http://www.postgresql.org/docs/7.4/static/xfunc-c.html
        regards, tom lane