jphickey
commented
2 years ago The specific instance of "RXC" described here was fixed by PR #137.
However, there are other instances of #define occurring at random locations within source files that should be fixed.
This issue was imported from the GSFC issue tracking system
Imported from: [GSFCCFS-1800] CF odd use of macro in CF_CFDP_R2_CalcCrcChunk Originally submitted by: Hickey, Joseph P. (GSFC-582.0)[VANTAGE SYSTEMS INC] on Wed Nov 17 10:25:30 2021
Original Description: This function appears to define a local macro inline just to avoid writing the same text a few times over. Example:
define RXC t->state_data.r.r2.rx_crc_calc_bytes
if (!RXC)
{
CF_CRC_Start(&t->crc);
}
The "RXC" is then used in a number of places later as well.
Normally one would either declare a local pointer to the value, or just simply a local temp variable to hold the value during computation, updating the global at the end of the routine.
The major issue with a macro like this is that it is not scoped to this function. The "RXC" string remains defined as a macro after this function, and may unexpectedly replace any other occurrence of this symbol later in the file, should it ever appear.