Error: (195) expression syntax

Question

I have a codebase that compiles for both a PIC18 and PIC24.

Whilst writing a driver for a new sensor on the PIC24, I recompiled for the PIC18 and the calculation of pressure fails:

{
    // Normal operation, valid data
    uint32_t rawPressure = ((ssc_sr_1[0] & 0x3F) << 8) + ssc_sr_2[0];
    filter_pressure_left = (uint16_t)(MIN_PRESSURE_PA + (rawPressure - MIN_PRESSURE_RAW)*(MAX_PRESSURE_PA-MIN_PRESSURE_PA)/(MAX_PRESSURE_RAW-MIN_PRESSURE_RAW));
}

On compile, the error i2c.c:546: error: (195) expression syntax (where line 546 is the filter_pressure_left = line) is thrown.

I cannot see anything syntactically wrong to throw this error, which is backed up by it not being thrown when compiling with xc16-gcc.

Compiler Versions:

XC16-GCC V1.23
XC8 V1.33

Additional information requested surrounding values used:

DECLARE unsigned char ssc_sr_1[2];
DECLARE unsigned char ssc_sr_2[2];
#define MAX_PRESSURE_PA                 249
#define MIN_PRESSURE_PA                 -249
#define MAX_PRESSURE_RAW                14745   // 90% of 2^14
#define MIN_PRESSURE_RAW                1638    // 10% of 2^14

Compiler message is the title of this question "Error: (195) expression syntax" and occurs on the second line. It is not an issue of wrong value returned, it is that the compiler will not accept that line - I included the line before due to previous questions asked about the error actually stem from missing semi-colons on the line before etc. — M Curry
I presume ssc_sr_1 is uint8_t or other 8-bit value? If not, potentially the compiler could be detecting an invalid operation. — Neil
Probably one of the compilers can't find the stdint.h types. Did you include that header and do both compilers support C99? Are both compilers configured to compile as C99? — Lundin
With the filter_pressure_left = line commented out, the code compiles, so it shouldn't be a stdint issue. — M Curry

M Curry M Curry · Accepted Answer · 2016-06-29T09:30:35

Spaces spaces spaces!

Changing the second line to:

filter_pressure_left = (uint16_t)(MIN_PRESSURE_PA + (rawPressure - MIN_PRESSURE_RAW) * (MAX_PRESSURE_PA - MIN_PRESSURE_PA) / (MAX_PRESSURE_RAW - MIN_PRESSURE_RAW));

compiles without error.

For reference to people coming across this in the future - split your equation to multiple lines to identify exactly which portion is failing - in my case (MAX_PRESSURE_PA-MIN_PRESSURE_PA) caused the error and absent-mindedly adding spaces and re-compiling cured it.

Error: (195) expression syntax

1 Answers