  --- Portuguese version
  As falhas de software est\~ao com frequ\^encia associadas a acidentes com
graves consequ\^encias econ\'omicas e/ou humanas, pelo que se torna imperioso
investir na valida\c{c}\~ao do software, nomeadamente daquele que \'e
cr\'itico. Este artigo endere\c{c}a a tem\'atica da qualidade do software
atrav\'es de uma an\'alise comparativa da usabilidade e efic\'acia de quatro
ferramentas de an\'alise est\'atica de programas em C/C++. Este estudo permitiu
compreender o grande potencial e o elevado impacto que as ferramentas de
an\'alise est\'atica podem ter na valida\c{c}\~ao e verifica\c{c}\~ao de
software. Como resultado complementar, foram identificados novos erros em
programas de c\'odigo aberto e com elevada popularidade, que foram reportados.
  --- English version
  Software bugs are frequently associated with accidents with serious
economical and/or human consequences, being thus imperative the investment in
the validation of software, namely of the critical one. This article addresses
the topic of software quality by making a comparative analysis of the usability
and efficiency of four static analysis tools for C/C++ programs. This study
allow to understand the big potential and high impact that these tools may have
in the validation and verification of software. As a complementary result, we
identified new errors in very popular open source projects, which have been
reported.
