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How to find out how many global memory variables are used?

In C / C ++, in the context of microcontroller programming, how can I find out how many global global variables are used (not counting new / distributed data)?

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If you use gcc to link the executable / firmware, you can add an option -Map=memory.mapto the command line.

In this file you will find something like this that tells you where the RAM is:

Memory Configuration

Name             Origin             Length             Attributes
FLASH            0x00014000         0x0002c000         xr
RAM              0x20002000         0x00002000         xrw
*default*        0x00000000         0xffffffff

Pay attention to the RAM address ( 0x20002000). Later you will find the addresses of global variables in RAM. The difference in addresses will tell you their size:

 .bss           0x20002924       0x94 C:/Users/...../main.cpp.o
                0x20002924                i2c
                0x20002934                ex1
                0x20002948                ex2
                0x2000295c                sensorI2C
                0x20002978                sensorSPI0
                0x2000299c                sdCard

(.bss) , , . - ( , , . (0x94) , main.cpp, .

. " " (, int a = 1;) .data, ! (, ) , ++, - .bss. .

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