pdfSetTextMapNumericCharNames

Map numeric character names to Unicode.
void pdfSetTextMapNumericCharNames(int map)
By default, XpdfText will attempt to map the numeric character names sometimes used in font subsets to Unicode. This often results in usable text, but sometimes it generates gibberish. Calling this function with a zero argument disables this behavior and tells XpdfText to discard text in fonts with questionable encodings.

This setting is global - it applies to all PDF handles.

C:
pdfSetTextMapNumericCharNames(0);