Get the content of an annotation.
char *pdfGetAnnotContent(PDFAnnotHandle annot, int *length)
This function returns the "content" of an annotation (whose handle was obtained with pdfOnAnnot). Only some annotation types have content; pdfGetAnnotContent will return NULL for annotations that don't have content.

A string is returned, and *length is filled in with the string length. The string will be zero-terminated, but it may contain zero bytes, depending on the current text encoding (see pdfSetTextEncoding). The caller is responsible for freeing the string (if non-NULL) with the pdfFreeMemory function.

void mouseDownCbk(void *data, int button, int shift, int page, double x, double y) { PDFAnnotHandle annot; char *type, *content; int contentLength; annot = pdfOnAnnot(viewer, page, x, y); type = pdfGetAnnotType(annot); if (!strcmp(type, "Text")) { content = pdfGetAnnotContent(annot, &contentLength); /* ... display the popup text annotation content ... */ pdfFreeMemory(content); } }